textproduct: Albany

WHAT HAS CHANGED

Added a light glaze of freezing rain tonight across the high terrain of the ADKs and southern Greens. Otherwise, little has changed with the multi-hazard storm tonight through tomorrow night, with gusty winds and heavy rain still expected.

KEY MESSAGES

1) High confidence for a storm system to bring gusty winds this evening through Tuesday, with rain, heavy at times tonight through tomorrow night. Ponding of water in urban /poor drainage areas, minor river flooding (mainly for New England), and a few power outages are all possible.

2) Rain changing to wet snow before ending Monday night into Tuesday could lead to slippery travel conditions, especially north and west of the Capital District.

DISCUSSION

KEY MESSAGE 1... Storm system that will impact our region tomorrow is currently taking shape over the southern Plains, with a 989 mb sfc low out ahead of an amplifying upper-level trough seen on GOES 16 WV imagery. Ahead of this system, our weather is tranquil, with partly to mostly clear skies under sfc high pressure. Temperatures range from the upper 10s to around 30 through the rest of tonight. As the sfc low to our west continues to amplify and track towards the Great Lakes today, it will help to lift a weak mid-level warm front across our region. This may result in a few light snow showers for the Catskills, Mohawk Valley, and ADKs this morning into early this afternoon, but any snow accumulations look minimal given very light precip. Despite mostly cloudy skies today, it will be warmer than yesterday with highs ranging from mid 30s to mid 40s. Winds also become gusty this afternoon into early this evening with the deepening low to our west, but the strongest winds will hold off until tonight.

.The upper trough continues to amplify over the center of the country, with the associated sfc low deepening to <980 mb as it tracks into the western Great Lakes tonight into tomorrow. The sfc warm front will lift northwards tonight, along with a weak upper impulse embedded in SW flow ahead of the deepening trough. The combination of increasing moisture and isentropic lift/warm advection will lead to areas of rain tracking from S/SW to N/NE across the region tonight, especially after midnight. With Showalter values dropping below 0, a few rumbles of thunder will be possible across the Mid Hudson Valley and western New England. For the high terrain of the ADKs and southern Greens, sfc temperatures will be near or just below freezing, so some patchy freezing rain will be possible here. Given marginal thermal profiles and fairly sparse coverage of freezing rain, have decided against winter weather advisory issuance for any of our zones in collaboration with BTV and GYX. Nevertheless, a few slick spots will be possible in these aforementioned areas, which we plan to handle with SPSs as needed. The strengthening southerly LLJ tonight will also lead to S/SE winds becoming gusty, especially in the favored west slopes of the Taconics and southern Greens where some downslope enhancement is expected, especially before precip arrives. However, gusts look to remain below advisory criteria at this time.

Tomorrow, a lull in the steady precip is expected for much of our region, although scattered to numerous showers linger across western New England. The LLJ continues to strengthen to 55-65+ kt Monday, but with abundant cloud cover, scattered showers, and a low-level inversion in place, there is some question as to how much of the wind will be able to mix down to the surface. Current forecast does have near advisory-level winds Monday afternoon, especially east of I-87. If confidence increases, then an advisory could be issued over the next 12-24 hrs. Strong warm advection Monday will also help temperatures rise well into the 50s to low 60s.

The system's cold front tracks through the region Monday evening into Monday night. Ahead of the front, PWATs surge to 1.1 to 1.25", which is near or potentially above the daily max per the SPC sounding climatology. Forcing looks quite impressive as well, with very strong low-level convergence along the front and impressive upper dynamics (CVA, right entrance of the upper jet nearby). This overlap of anomalous moisture and forcing will result in heavy rain with the frontal passage. WPC has most of our area in a marginal risk ERO. While flash flood potential looks rather low due to the somewhat progressive nature of the cold front, ponding of water in the typical urban/poor drainage areas certainly looks possible. With total QPF amounts of 1-2" (locally higher amounts possible in southwestern New England and the Catskills), rises on main stem rivers are expected, with the NERFC, along with the HEFS and NAEFS ensembles continuing to show a low to moderate chance for minor flooding on a few main stem rivers, mainly in western New England. Will also note that while much of the river ice was flushed out last weekend, any lingering river ice (mainly in the ADKs) may be broken up by the runoff from the rain, so additional isolated ice jam issues in the ADKs can't be ruled out.

Other thing to mention with this frontal passage is severe weather threat. There looks to be a narrow cold frontal rainband crossing the region ahead of the cold front Monday evening within a high shear/low CAPE environment. For most of our area, timing of the cold frontal passage looks to be after sunset, which should limit the amount of surface based instability. That said, given strong forcing and very strong low-level jet, even modest SBCAPE values would be sufficient for this line of convection to mix strong wind gusts down to the sfc. While confidence is low whether or not this will happen, SPC does have our southwestern zones in a marginal risk for severe weather.

KEY MESSAGE 2... Temperatures quickly drop below freezing behind the cold front Monday night. The falling temperatures should allow for rain to change over to wet snow, especially for areas north and west of the Capital District where up to a couple inches of new snow will be possible. Any areas that see snow could see some slippery road conditions, and even areas that see mainly rain could have a few slick spots with temperatures dropping quickly behind the front. Precipitation comes to and end for most of the region by Tuesday morning, but with a very cold airmass moving in behind the departing sfc low (850 temps to around -18C), lake effect snow showers are expected through Tuesday night/early Wednesday across the western ADKs and possibly western Mohawk Valley. Up to a few additional inches of additional snow will be possible, especially in the ADKs.

Will also mention that winds look quite gusty behind the departing front on Tuesday. Deep mixing within the low-level cold advection regime should support wind gust to near advisory criteria, especially in the normal W/NW channeled flow areas of the Mohawk Valley, Capital District, and Berkshires. Wind advisories will likely be needed as we get closer in time.

With the very cold airmass overhead, temperatures will be several degrees below normal Tuesday with highs only in the 20s to 30s. Temperatures Wednesday remain below normal as well, but should moderate back near or above normal for Thursday through the first half of next weekend. Once the lake effect snow showers end, generally non-impactful weather expected through the end of next week, although a couple of shortwaves embedded within NW flow aloft could bring some light valley rain/high- terrain snow showers at times through the end of the week.

AVIATION /12Z SUNDAY THROUGH THURSDAY/

IR satellite imagery show a band of mid level clouds is currently increasing over the region. These clouds are associated with a warm front lifting across the region. Despite the clouds, there is no precip reaching the surface just yet, as any precip aloft is dissipating before reaching the ground, so flying conditions continue to be VFR this morning with bkn cigs around 10-12 kft. Surface winds will remain very light to calm.

As the warm front lifts northward, a snow shower may come close to KGFL towards midday, so will allow for a VCSH there. Otherwise, it will be continued dry. Ceilings will be lowering during the morning hours, with bkn-ovc cigs around 5 kft by the mid to late morning hours for all sites. After light and variable winds early, south to southeast winds will increase for the afternoon as the warm front passes. A few gusts up to 25 kts are possible by late in the day at KALB, but lighter winds are expected for the other sites.

With the persistent southerly flow, increasing low level moisture will allow for MVFR stratus to move in for all sites after 01z this evening. South to southeast winds will be around 10 kts, with some higher winds/gusts at KALB. Some LLWS will be possible this evening where surface winds remains lighter, as 2 kft will be around 40-45 kts from the southeast. A period of light rain will move from south to north for the late night hours, bringing MVFR visibility and ceilings for all sites after about 06z-08z.

Outlook...

Monday Night: High Operational Impact. Windy With Gusts To 38 kts. Definite RA...SN. Tuesday: Moderate Operational Impact. Windy With Gusts To 37 kts. NO SIG WX. Tuesday Night: Moderate Operational Impact. Windy With Gusts To 30 kts. NO SIG WX. Wednesday: No Operational Impact. NO SIG WX. Wednesday Night: No Operational Impact. NO SIG WX. Thursday: Low Operational Impact. Slight Chance of RA...SN. Thursday Night: Low Operational Impact. Slight Chance of RA. Friday: Low Operational Impact. Slight Chance of RA.

ALY WATCHES/WARNINGS/ADVISORIES

CT...None. NY...None. MA...None. VT...None.